The present invention relates to a pneumatic cylinder apparatus. More particularly, the present invention relates to an improved cylinder design which increases flexibility and reduces the amount of space required for mounting or installing the cylinder.
The present invention is also designed to reduce the number of different parts required to manufacture the cylinder. The cylinder of the present invention uses symmetrical parts which can be interchanged at opposite ends of the cylinder. Therefore, parts such as tube seals and pilot rings may be used at either end of the cylinder. The cylinder of the present invention includes parts which have a similar shape regardless of the bore size of the cylinder. The parts are scaled to match the desired bore size. This common configuration between the parts simplifies automation and minimizes the requirements for manual machine set-ups.
A typical compact cylinder arrangement includes air supply fittings coupled to ports formed in opposite ends of the cylinder to move the piston back and forth within the cylinder. When the fittings and air supply tubes are added to conventional cylinders, the overall envelope size is increased in two planes. This causes problems when attempting to mount a conventional cylinder in a location where space is limited.
The cylinder of the present invention advantageously locates both control ports and both fittings at a single end of the cylinder. This permits increased flexibility for mounting the cylinder of the present invention. Therefore, the compact cylinder of the present invention can fit into smaller spaces than conventional cylinders. When both of the ports for controlling movement of the piston back and forth within the cylinder are located at a single end of the cylinder, a symmetrical tube seal of the present invention can be altered at the end of the cylinder opposite the ports to permit pneumatic communication between first and second air passages within the cylinder.
In addition, having both control ports located at a single end of a cylinder facilitates manifold mounting of a pneumatic valve. No external tubes or special adapters are required. Therefore, the cost of adding the pneumatic valve is reduced.
According to one aspect of the present invention, a cylinder apparatus includes a piston and a cylinder tube having a first end and a second end. The cylinder tube is formed to include a central bore extending from the first end to the second end for receiving the piston therein and a second bore extending from the first end to the second end spaced apart from the central bore. The cylinder apparatus also includes a first end cap coupled to the first end of the tube and a second end cap coupled to the second end of the tube. The first end cap is formed to include means for communicating air between the central bore and the second bore adjacent the first end of the cylinder tube. The second end cap is formed to include a first port in communication with the central bore of the tube and a second port in communication with the second bore.
According to another aspect of the present invention, the means for communicating air between the central bore and the second bore adjacent the first end of the cylinder tube includes a notched section formed in the first end cap to permit air flow through the notched section from the central bore to the second bore.
According to yet another aspect of the present invention, a first seal is located between the first end cap and the first end of the cylinder tube. The first seal permits air to pass between the central bore and the second bore adjacent the first end of the cylinder tube. The first end cap is formed to include a groove therein for receiving the first seal.
A second seal is located between the second end cap and the second end of the cylinder tube. The second seal blocks air flow between the central bore and the second bore of the cylinder tube adjacent the second end of the cylinder tube. The second seal includes a first section disposed adjacent the central bore, a second section coupled to the first section and disposed adjacent the second bore, and a divider located between the first section and the second section to block air flow between the first and second bores. The second end cap is formed to include a groove therein for receiving the second seal.
A notched section may be formed in the first end of the cylinder tube between the central bore and the second bore of the cylinder tube to increase the amount of air flow from the central bore to the second bore of the cylinder tube adjacent the first end of the cylinder tube. When the notched section is formed in the first end cap, first and second seals having a substantially identical shape may be used.
According to still another aspect of the present invention, the moving means comprises means for selectively coupling the first port to a pressure supply and the second port to an exhaust to move the piston in a first direction within the cylinder tube, and for selectively coupling the second port to the pressure supply and the first port to the exhaust to move the piston in a second direction within the cylinder tube.
According to a further aspect of the present invention, a piston rod is coupled to the piston. The second end cap coupled to the second end of the tube is a head cap formed to include an aperture therein configured to receive the piston rod therethrough. Means for moving the piston back and forth inside the central bore of the cylinder tube includes a first port in communication with the central bore of the tube and a second port in communication with the second bore. The first and second ports are selectively formed in one of the end cap or the head cap, depending upon the application specified by the customer. Therefore, the present invention advantageously permits both control ports to be selectively formed at either end of the cylinder. The end can be selected depending on the desired use for the cylinder.
Additional objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considering it in conjunction with the accompanying drawings.